Loher et al.: Growth of Pcrolithodes camtschoticus 
579 
~30 mm for males and females, respectively (Fig. 5, Table 
6); these crabs were most likely ~2.9 years of age and rep- 
resented the year class that settled in 1976. Males of this 
year class grew to a mean CL = ~88 mm by 1983 and the 
mode became indistinguishable in 1984; females grew to 
a mean CL = ~84 mm by 1983, and -92 mm by 1984 (Fig. 
5, Table 6). The second strong year class was evident from 
1994 to 1999 (Fig. 6, Table 6) and first appeared at larger 
sizes than did the 1976 year class. Males first appeared at 
a mean CL = -54 mm and grew to a mean CL = -137 mm 
in 1999; females first appeared at -53 mm CL in 1994 and 
grew to -109 mm in 1999. This year class first appeared 
at sizes that were essentially equivalent to the sizes that 
individuals from the 1976 year class had attained at age 
3.9. Thus, this second year class most likely represented 
crabs that settled in 1990. 
For both year classes, growth of males and females 
was similar up to -85 mm CL, after which females grew 
more slowly than males. However, the growth rates of 
the two year classes were not equivalent: the 1976 year 
class grew slower than the 1990 year class (Fig. 7) be- 
cause the 1976 year class required two years (from 1980 
to 1982) to progress from a mean CL = -50 mm to mean 
CL = -70 mm, whereas the 1990 year class achieved this 
level of growth within a single year (from 1994 to 1995). 
Mean sizes during the following two years of growth 
(from 1982 to 1984 for the 1976 year class; 1995 to 1997 
for the 1990 year class, Table 6) were similar between 
year classes. 
Within all of the annual length-frequency distributions, 
considering only size modes with mean CL <100 mm, 24 
modes were identified for both males and for females. 
These included the modes presented previously for the 
1976 and 1990 year classes, and an additional 16 modes 
for males, and 14 modes for females. The additional modes 
represent other year classes whose modal progression 
Table 5 
Characteristics of seasonalized Gompertz growth curves 
fitted to size-at-age data from Bristol Bay, Unalaska Island, 
and Kodiak Island. Values are reported for ages 0.9, 1.9, 
and 2.9 because these ages roughly correspond to trawl 
survey data: the trawl survey typically occurs in late May, 
-0.9 years following the previous year’s settlement. For all 
curves, L max = 200 mm CL. See “Materials and methods” 
section for definitions of model parameters. 
Model 
Bristol 
Unalaska 
Kodiak 
parameters 
Bay 
Island 
Island 
r 2 (fit) 
0.968 
0.922 
0.995 
K 
0.415 
0.421 
0.634 
C 
1.000 
0.275 
0.599 
t s (year) 
0.553 
0.535 
0.680 
Kun <y ear > 
-3.922 
-3.286 
-2.659 
Length estimates from the models 
age 0.0 
3.1 
3.6 
2.7 
age 0.9 
7.0 
14.5 
9.9 
age 1.0 
8.5 
16.4 
11.7 
age 1.9 
19.5 
34.5 
38.0 
age 2.0 
22.7 
37.6 
42.2 
age 2.9 
41.9 
62.7 
— 
age 3.0 
46.7 
66.4 
— 
Slowest growth in 
January 
January 
February 
could not be tracked for a substantial period of time. 
The mean CL (±1 SD) of all 24 male and female inodes 
is presented in Figure 8, plotted sequentially by increas- 
Summary of mean 
FiSAT. 
size (±1 SD) of the cohorts depicted in 
Table 6 
size-frequency progression plots (Figs. 5 and 6), as determined with 
Year class 
Year 
Male mean size (mm) 
±1 SD 
Female mean size (mm) 
±1 SD 
Age 
(years after settlement) 
1976 
1979 
31.9 ±2.79 
29.6 ±2.04 
2.9 
1980 
50.7 ±4.10 
50.2 ±3.40 
3.9 
1981 
63.2 ±5.06 
64.0 ±5.73 
4.9 
1982 
70.1 ±7.50 
71.4 ±8.20 
5.9 
1983 
88.4 ±14.74 
83.5 ±11.23 
6.9 
1984 
cohort indistinct 
92.3 ±4.84 
7.9 
1990 
1994 
54.1 ±4.67 
52.7 ±3.75 
3.9 
1995 
73.4 ±4.90 
71.9 ±7.28 
4.9 
1996 
86.5 ±8.01 
83.5 ±5.89 
5.9 
1997 
104.2 ±8.44 
97.4 ±3.62 
6.9 
1998 
117.8 ±11.40 
105.3 ±8.01 
7.9 
1999 
136.5 ±11.92 
109.3 ±7.79 
8.9 
